1. Field of the Invention
The present invention relates generally to printers and, more particularly, to an improved printer paper feeder for feeding continuous paper.
2. Description of the Related Art
Printers which have continuous paper feeders are generally known. A typical such feeder has a pair of front and a pair of back pin tractors disposed on a paper feeding route. A platen roller is positioned therebetween. Each tractor has a plurality of rotatable pins. The pins are arranged to engage with holes formed on both side ends of a continuous paper. Thus, the rotating motion of the pins will feed the continuous paper.
In order to set the continuous paper in the above feeder, the tip of the paper is first set at the back pin tractors. Then, the back pin tractors are rotated to feed the paper tip to the front pin tractors via the platen roller so as to position the tip at the front pin tractors. However, when the paper is tensed to be set in the front pin tractors, the holes at the paper rarely geometrically correspond to the pin positions of the front pin tractors. Thus, the paper usually has a looseness between the front and back tractors when it is set. Accordingly, users have to manually adjust the front pin tractors' position to remove any slack in the paper.
However, such manual adjustments are troublesome. Therefore, feeders which automatically remove the looseness of the continuous paper have been proposed.
In such feeders, the continuous paper also has a looseness between the front and back pin tractors at setting. After such setting is finished, the pins of the back pin tractors rotate in reverse. At this time, a mechanism such as a one-way spring clutch or the like cuts off the drive transfer to the front pin tractors. Accordingly, the back pin tractors pull the paper backward while the front pin tractors remain stationary and thus remove the looseness of the paper between the front and back pin tractors.
In the aforementioned feeder, the continuous paper may also be set from the bottom of the printer or the like without passing through the back pin tractors. In this case, a paper feed is performed only by the front pin tractors. If the paper is fed only frontward, there is no problem. However, it may occasionally be necessary to feed the paper a relatively large distance backward, such as when enlarged letters or the like are to be printed. In such cases, the one-way spring clutch or the like prevents the front pin tractors from rotating in reverse and thereby prevent the retraction of the continuous paper.